Lithonia is a city in eastern DeKalb County, Georgia, United States, as well as a collection of unincorporated communities in which it shares its name. Lithonia's city population was 1,924 at the 2010 census and a community population of about 15,000. Lithonia is in the Atlanta metropolitan area.
"Lithonia" means "city/town of stone". Lithonia is in the heart of the Georgian granite-quarrying and viewing region, hence the name of the town, from the Greek λίθος lithos, for stone. The huge nearby granite dome, Stone Mountain, is composed largely of a rock called Lithonia gneiss, a form of granite. The area has a history of rock quarries. The mines were served by the Georgia Railroad and Atlanta, Stone Mountain & Lithonia Railway. Some of the rock quarries have been converted to parkland and the railines to rail-trail.